Process for stabilizing gasoline and the like



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083 sierra V 5. 2.063516 UNITED STATES PATENT OFFICE"- PROCESS FOR STABILIZING GASOLINE,

AND THE LIKE Jacque C. Morrell, Chicago, 111., assignor, by mesne assignments, to Universal Oil Products Company, Chicago, 111., a corporation of Delaware No Drawing. Application November 11 1929,

Serial No. 406,517

Claims.

This invention relates to stabilization of gasolines, and more particularly to the prevention of color formation and gum forming substances in gasoline, and also to prevent the reduction Generally speaking, cracked gasolines are.

' composed of mixtures of hydrocarbons, princi-- pounds such as diolefins, terpenes, and related compounds. Oxidation products of the various hydrocarbons present in the gasolines are appar ently responsible also for the changes noted.

The formation of color in gasolines is undesirable mainly from a marketing viewpoint 'for changes in color are usually accompanied by the formation of gum-like and. polymer-like materials which affect not only the sale of the gasoline when dispensed from visible bowls, but ,also the operation of the motor owing to clog- 40 ging of. the gasoline feed lines, interference with the proper operation of: the carburetor, and the sticking of valves in the motor. Gum formation is likewise objectionable for the same reasons. The gum content of' a gasoline ;is measured by a test which involves the gum formation.

The present test is stated in terms of milligrams of gum formed upon the evaporation of a specific volume of the gasoline, namely, 100 cc. The presence of. oxygen during evaporation increases the gum formation, but as this condition is one which is present in the'use of the gasoline, it has a bearing upon its performance in the motor. The so-called gum contentv of the gasoline will also vary as a function of the material in which it is evaporated, for example,

involve that when gasolines are in the presence of copper, the resulting gum will be very much higher than in glass. These tests have a bearing upon the performance of the I gasoline in the motor and its auxiliary feed system, and the beneficial effects of my inven- 5 tion will be indicated by such tests as well as by actual motor tests.

The antiknock property of a gasoline is among its most important and valuable characteristics. The higher the antiknock value or 10 rating of a gasoline, the more efilcient it is as a motor fuel. Knocking in a motor is an index of inefiicient operation because energy which otherwise would be utilized in the operation of the motor must be dissipated by rapid cooling, 15 and unless this remedy isrestorted-to, acondition will be set up where auto-ignition occurs, thus interfering with the normal functioning of the motor. It has been observed that the high-' er the compression pressure or compression 20 ratio of a motor, the greater the tendency for a given fuel to knock, and inasmuch as the -ef- 'ficiency of a moto'r increases with compression pressure and compression ratio, it is desirable that a motor fuel possess sufficiently high antiknock properties to avoid knocking. The present tendency is to increase. the compression pressure of motors in order to increase their efliciency or mileage per gallon of fuel consumed sothat antiknock fuels are at a premium.

The change in antiknock rating during storage of a,motor.';'f-uel is particularly embarrassing in that although the antiknock rating of a tank of motor fuel is established and found to be satisfactory, there is a complete uncertainty as 35 to its antiknock value at the time of sale. The economic loss of restoring such gasolines to their original antiknock value can be realized from cases which have been observed where the antiknock value has dropped from approxi 40 mately fifty percent benzol equivalent to zero percent over a period of several months standing.

I I have discovered that when relatively small amounts, for example-from a' trace up to two 45 percent, more or less, of the inhibiting or stabilizing agents which are the subject of this in.

' vention are added to a gasoline which shows a naturally occurring or under accelerated conditions.

I have discovered that phthalic acid and its derivatives, such as the phthalates, phthalic anhydride, phthalides, and the amino and amido derivatives, phthalins, phthaleins, and others, when added to motor fuels, especially cracked gasoline, are capable of accomplishing the stabilizing and inhibiting effects above pointed out, more particularly with respect to the stabilization of color and antiknock values, and in the As examples of the color stabilizing properties" of phthalic acid -and its derivatives, I may cite the following: 1

Starting with a gasoline of 18 color, which on exposure to diffused sunlight for-several days dropped to 14, Ihave found that by the addition of approximately 0.1% of phthalic acid and some of its derivatives that the resultant color under similar conditions of exposure is 20, actually showing an improvement in color with the stabilizer.

Similarly I .have found that with certain gasolines showing a marked tendency to-depreciate in antiknock value without the addition of phthalic acid and-its derivatives one can by the addition of approximately 0.1% of phthalic acid avoid such depreciation. As an example a cracked gasoline upon storage without the use of my reagents dropped in antiknock value to zero benzol equivalent from a value of approximately 35% benzol equivalent when stored for several months. Upon the addition of 0.1% of phthalic acid this depreciation in benzol equivalent or antiknock rating was prevented under similar conditions of storage. I have found further that under accelerated conditions of depreciation in antiknockvalue, for example exposure of a cracked gasoline to the action of oxygen at elevated temperatures, which ordinarily caused a very marked depreciation in antiknock value, that such depreciation would be'prevented by the addition of small amounts of phthalic acid.

Stabilization of gum formation was also observed, for example with a gasoline showing a less than 1%.

aoeasic gum content of 15 milligrams by the copper dish test. No substantial increase in the gum formation was observed, after a long period of storage or exposure of the gasoline to which a small quantity of resorcinol or its derivatives was added.

It can be appreciated that the present invention is of prime importance to the oil refining industry since it assures a stable product after refining, and at the same time avoids a large expenditure in bringing out the antiknock properties of depreciated gasoline by the addition of costly antiknock dopes or hydrocarbons, for example benzol. These inhibitors are not to be confused with antiknock dopes because the amount added will impart practically no antiknock properties per se, but simply acts to prevent the loss of antiknock and other desirable properties of the gasoline.

The above examples are given by way of illustration only, and are not to be construed as limitations upon the spirit and broad scope of the invention. I

I claim: e

1. The process of stabilizing gasoline which comprises the addition thereto in amount up to about 2% of a compound containing the phthalic acid radical and selected from the 'group consisting of the phthalides, phthalic acid and phthalic anhydride.- 4

2. A motor fuel comprising gasoline contain ing up to about 2% of a compound containing the phthalic-acid radical and selected from the group consisting of the phthalides, phthalic acid and phthalic anhydride.

3. The process of stabilizing gasoline which comprises the addition of phthalic anhydride thereto in amount up to about 2%.

'4. A motor fuel comprising gasoline containing up'to about 2% phthalic anhydride.

5. A motor fuel comprising gasoline containing up to about 2% phthalic acid.

6. The process of stabilizing gasoline which comprises the addition of phthalic acid thereto in amount up to about 2%. L

'7. A cracked motor fuel containing a phthalide substance in an amount sufficient to inhibit gum formation.

8. A motor fuel containing unsaturated gum forming constituents and a phthalide substance in an amount sufficient to inhibit gum formation.

9. A cracked motor fuel according to claim 7, in which the amount of a phthalide substance is less than 1%.

10. A motor, fuel according .to claim 8, in which the amount of a phthalide substance is JAcQUn c. MORRELLJ 

